1. Field of the Invention
The present invention relates to a multidirectional input device, and more particularly, to a multidirectional input device in which a plurality of electric parts can be simultaneously operated by manipulating a control shaft.
2. Description of the Related Art
In a conventional multidirectional input device, as shown in FIGS. 14-16, a first interlock member 31 curved in an arch form is placed inside a box-shaped frame 30 that is surrounded by side plates and is open at the bottom. The first interlock member 31 has mounting portions 31a at both ends, and is turnably laid in the frame 30 with the mounting portions 31 fitted in holes 30a and 30c formed in the side plates of the frame 30.
The end faces of the mounting portions 31a are provided with holes 34 with which rotation shafts 33 of variable resistors 32 serving as rotary electric parts are engaged. The arched portion of the first interlock member 31 has a slot 35 extending in the longitudinal direction.
Below the first interlock member 31, a second interlock member 40 is positioned to extend in a direction intersecting the first interlock member 31. The second interlock member 40 is made of metal by die-casting or by other methods, and has a spherical portion 41 at the center. Arm portions 42 horizontally extend right and left from the spherical portion 41. Circular mounting portions 42a project at the leading ends of the arm portions 42, and are fitted in holes 30b and 30d formed in the frame 30, whereby the second interlock member 40 is rotatably supported in the frame 30.
Holes 43 are formed in the end faces of the mounting portions 42a, and rotation shafts 33 of variable resistors 32 are press-fitted and engaged with the holes 43.
A slot 45 vertically penetrates through the center of the spherical portion 41. The first and second interlock members 31 and 40 are positioned so that the slot 35 and the slot 45 intersect.
A control shaft 36 is passed through the slot 45 of the second interlock member 40. The control shaft 36 is made of metal or the like, and has an oval support portion 38 at the center. Sticklike columns formed integrally with the support portion 38 vertically protrude from the top and bottom thereof.
A disklike spring bearing 47 is formed integrally with the control shaft 36 at a position of the downward protruding column close to an end portion 36a. 
The support portion 38 of the control shaft 36 has a small hole 39. The small hole 39 and a hole 44 formed through the second interlock member 40 are aligned with each other, a round pin 46 of a metal or the like is inserted or press-fitted in the aligned holes 39 and 44, and both ends of the round pin 46 are caulked, whereby the control shaft 36 is tiltably mounted in the second interlock member 40.
The column of the control shaft 36 extending upward from the support portion 38 is passed through the slot 35 of the first interlock member 31. By tilting the control shaft 36 in the direction along the slot 35, the second interlock member 40 can be turned or rotated on the mounting portions 42a. A grip 55 is fixedly mounted at the upper end of the control shaft 36 that extends upward through the slot 35.
An operating member 37 made of resin or the like and having a saucerlike outer shape is mounted at the bottom end portion 36a of the control shaft 36. The operating member 37 has a boss portion 37a projecting at the center, and the end portion 36a of the control shaft 36 is inserted in a hole 50 formed through the boss portion 37a, thereby allowing the operating member 37 to move vertically.
A bottom plate 49 is positioned to close the open bottom of the frame 30. The bottom of the operating member 37 is in elastic contact with the bottom plate 49.
The first interlock member 31 can be turned on the mounting portions 31a by tilting the control shaft 36 on the round pin 46 along the slot 45 of the second interlock member 40, and the second interlock member 40 can be turned on the mounting portions 42a by tilting the control shaft 36 in the direction along the slot 35 of the first interlock member 31.
The rotation shafts 33 of the variable resistors 32 retained on the side plates of the frame 30 are press-fitted in the holes 34 and 43 of the first and second interlock members 31 and 40, respectively, so that the first and second interlock members 31 and 40 and the variable resistors 32 move together.
A substantially conical return spring 48 is placed between the spring bearing 47 of the control shaft 36 and the inner bottom face of the operating member 37. The operating member 37 is elastically contacted with the bottom plate 49 by elastic force of the return spring 48, so that the control shaft 36 is biased in the neutral upright position.
The operation of the conventional multidirectional input device will be described below. First, as shown in FIG. 15, when the control shaft 36 is in a non-operation state, it is in the neutral upright position with its upper end protruding up from a hole 56 of the upper side plate of the frame 30, and the operating member 37 is horizontally placed in elastic contact with the bottom plate 49 by the return spring 48.
By tilting the control shaft 35 from the neutral state along the slot 45 of the second interlock member 40 (for example, rightward or in the clockwise direction, as shown in FIG. 16), the first interlock member 31 is turned or rotated. This in turn operates the variable resistor 32 to change the resistance thereof.
With the tilting operation of the control shaft 36, the operating member 37 is tilted, as shown in FIG. 16, and a part of the rim of the tilted operating member 37 moves in sliding contact with the inner bottom face of the bottom plate 49. With this, the operating member 37 moves toward the circular spring bearing 47, thereby compressing and bending the return spring 48.
When operating force applied to the control shaft 36 is removed, the elastic force of the return spring 48 causes the tilted operating member 37 to move in sliding contact with the inner bottom face of the bottom plate 49, which moves toward the horizontal position with respect to the inner bottom face of the bottom plate 49, and the control shaft 36 automatically returns to the neutral upright position shown in FIG. 15.
In order to operate the variable resistor 32 engaged with the arm portion 42 of the second interlock member 40, the second interlock member 40 is turned by tilting the control shaft 36 along the slot 35 of the first interlock member 31, thereby changing the resistance of the variable resistor 32.
In the tilting operation, the control shaft 36 contacts the end of the slot 35 of the first interlock member 31 or the end of the slot 45 of the second interlock member 40, thereby constructing a stopper for the tilting operation.
The control shaft 36 can also circulate around the round pin 46 in the tilted state shown in FIG. 16.
The end portion 36a of the control shaft 36 is fitted in the circular hole 50 of the operating member 37. When the control shaft 36 is circulated, the bottom of the operating member 37 is elastically pressed against the bottom plate 49 by the return spring 48, and friction arises between the bottom of the operating member 37 and the bottom plate 49. Since this frictional force is greater than that between the end portion 36a and the hole 50, the operating member 37 also circulates while the bottom of the operating member 37 slips on the bottom plate 49.
In the above-described conventional multidirectional input device, however, since the end portion 36a of the control shaft 36 is fitted in the circular hole 50 of the operating member 37, when the control shaft 36 is circulated in the tilted state, friction arises between the bottom of the operating member 37 and the bottom plate 40 because of elastic pressing by the return spring 48. For this reason, the bottom of the operating member 37 moves while slipping on the bottom plate 49, and the slip is transmitted to the control shaft 36, or the operating member 37 is chipped and changes its shape, which impairs the manipulation feeling.
Accordingly, it is an object of the present invention to provide a multidirectional input device with a superior manipulation feeling.
According to a first arrangement for overcoming the above problems, there is provided a multidirectional input device including: a frame; first and second interlock members turnably mounted in the frame so as to intersect each other; a control shaft placed perpendicularly to the first and second interlock members and held by the second interlock member so as to be tilted to turn the first and second interlock members; a bottom plate placed so as to intersect the axial direction of the control shaft; an operating member held by the control shaft to move in the axial direction of the control shaft; an urging member for elastically pressing the bottom of the operating member against the bottom plate; and electric parts operated via the first and second interlock members by the tilting operation of the control shaft, wherein the control shaft and the operating member are spline-connected.
According to a second preferred arrangement, the control shaft is provided with a cylindrical portion for holding the urging member, and the inner wall of the cylindrical portion and the outer wall of the operating member are spline-connected.
According to a third preferred arrangement, the control shaft is provided with a plurality of ribs extending in the axial direction, and is spline-connected by fitting the ribs in grooves formed in the operating member.
Further objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.